Property developers Nick and Christian Candy have defeated a £132m damages action in the High Court.
Mark Holyoake, a former friend of Nick Candy, had sought the damages, arguing he suffered losses and received threats to himself and his family after borrowing £12m in a loan deal.
But Mr Justice Nugee ruled none of Mr Holyoake's claims were proven.
He also said: "None of the protagonists emerge from the trial with great credit."
"Each has been shown to have been willing to lie when they consider their commercial interests justify them doing so."
The judge said Mr Holyoake had "repeatedly lied" and that "he and his associates resorted to forgery, deceit and impersonation".
He also said: "Christian Candy, with the encouragement of his brother, told a series of deliberate lies to Mr Holyoake."
In a statement released after the case, the Candys, who have always denied the allegations, said: "It has taken a great deal of time and effort to win this case, and it has caused unwarranted damage to our personal and business lives.
"The claim should never have been brought."
The brothers are best known for creating the luxury One Hyde Park apartment complex in Knightsbridge, in central London.
The dispute arose after Christian Candy's company CPC lent Mr Holyoake £12m to help him buy and redevelop luxury apartments in Belgravia.
The deal went sour and Mr Holyoake claimed he was intimidated.
Mr Holyoake said he paid back more than £37m on the two year loan and incurred millions of pounds in legal fees and other costs.
Mr Holyoake, whose company was also part of the action, said in a statement: "We, the claimants, are in a state of disbelief that Mr Justice Nugee has not ruled in our favour and intend to seek an appeal with immediate urgency.
"Anyone reading today's judgement will see that there are currently no winners here.
"I stand by our allegations and maintain that my own actions were deployed in self protection and wholly justified in the circumstances."